1. Technical Field
The invention generally relates to electronic music controllers, and more particularly to pressure-controlled transitions played on electronic musical instruments.
2. Related Art
Electronic music controllers in which the positions of one or more fingers on a playing surface are detected come in a variety of formats. For example, a standard MIDI keyboard operates by having separate keys, each of which can be pressed by a user and represents a discrete pitch. The loudness of the pitch can be adjusted by the amount of pressure pressed down on the key (polyphonic aftertouch). In MIDI wind controllers, which emulate instruments such as saxophones or clarinets, pitches are similarly determined by the combination of keys depressed by the performer. Wind controllers continually monitor the airflow of the performer's breath, and the pressure of the performer's lips and teeth on the embouchure.
Continuous-pitch electronic controllers, such as Haken Audio™ Continuum™ Fingerboard, are also available. The Continuum Fingerboard is discussed in U.S. Pat. No. 6,703,552, which is incorporated herein by reference. The Continuum Fingerboard provides a continuous surface upon which a user can press one or more fingers. The Continuum Fingerboard then provides three-dimensional coordinates corresponding to focal points of the pressure provided by the user's fingers. This three dimension system may be applied such that left-and-right (x-axis) corresponds to pitch, up-and-down (z-axis) corresponds to loudness, and forward-and-back (y-axis) corresponds to timbre.
The Continuum Fingerboard can operate as a polyphonic or monophonic instrument. It can also employ pitch correction, such as that discussed in pending U.S. patent application Ser. No. 11/251,443, filed on Oct. 15, 2006 and herein incorporated by reference.
In such music devices, single-note lines can be performed with a variety of transitions between notes. If one finger is down, and another is pressed, the synthesizer can perform this as two consecutive single notes with different transitions between the notes. Any of the following transitions may be used:
Retrigger: The second note has an attack and decay; it sounds much like it would if the first note had not been played.
Legato: The second note has no attack or decay of its own; instead, it continues with the sustain portion of the first note, but jumps to the new pitch.
Portamento: The second note has no attack or decay of its own; instead, it continues with the sustain portion of the first note, but smoothly glides to the new pitch. The duration of the pitch glide is a separately configured parameter.
These types of transitions have been previously implemented both on analog and digital synthesizers. Traditionally, a foot switch or other control device has been used to indicate that the synthesizer should perform single-note lines, instead of playing polyphonically, when multiple fingers are down. In the traditional implementation in which the device is in single-note performance mode, the transition occurs as soon as the second finger depresses the key on the keyboard. These previous implementations leave much to be desired.
For example, in a standard MIDI keyboard environment, portamento can be applied by preprogramming the amount of time that should transpire for the transition from the first pitch to the second pitch. For example, a keyboard can apply a “slide up” from an A to an F by calculating intervening pitches and playing them according to a predetermined time setting. However, it is difficult for the user to control the speed or apply different pitch trajectories in a portamento transition. More particularly, the user cannot control the portamento time or pitch trajectory merely by the placement of his or her fingers on the playing surface.